# Feeling Froggy? (DD-758)

> The wood frog (Lithobates sylvaticus), found across North America from the American Midwest and southern Canada to Interior Alaska, can survive with about 65-70% of its body water frozen. While frozen it shows no heartbeat, breathing or circulation. It builds up urea before winter and floods its tissues with glucose from the liver when ice starts to form; both act as cryoprotectants that limit ice formation and cell shrinkage. When temperatures rise in spring, the frog thaws, its heart starts beating again, and normal functions resume. The footage, credited to Nat Geo Animals, shows wood frogs in water and a close-up of a frog's eye.

- Department: Nature (also Science)
- First published: 2026-10-25
- Last updated: 2026-10-25
- Permalink: https://detailenjoyer.com/case/feeling-froggy/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-758-F01**: Lithobates sylvaticus. _(Write-up · Exhibit A (Species))_
- **DD-758-F02**: North America, to Interior Alaska. _(Write-up · Exhibit B (Range))_

## Write-up

Wood frogs can freeze solid in winter and thaw back to life. Their hearts stop until spring.

1. **Species**: Lithobates sylvaticus.
2. **Range**: North America, to Interior Alaska.
3. **Frozen water**: Up to about 65-70%.
4. **Vital signs**: None while frozen.
5. **Protectants**: Glucose and urea.

## Related case files

- [Frozen Gators (DD-491)](https://detailenjoyer.com/case/frozen-gators/): Another animal that rides out a deep freeze

## Reel vs. record

- **Note**: The Reel calls glucose and urea 'cytoprotectants'; the standard term is cryoprotectants. I kept the Reel's wording in the transcript.

## Video: Feeling Froggy?: Wood Frogs Can Freeze Solid in Winter and Thaw Back to Life

- Duration: 24.3 s · Published: 2026-10-25
- File: https://detailenjoyer.com/assets/videos/De7tRK9x39E.mp4

### Transcript

Did you know? Wood frogs can survive being frozen solid during winter, with their hearts stopping and as much as 65% of their body water turning to ice. Found across North America, these amphibians survive temperatures that would kill most other vertebrates by flooding their tissues with glucose and urea, which act as natural cytoprotectants. When spring arrives and temperatures rise, the ice melts, their hearts start beating again, and normal bodily functions resume. NOW YOU KNOW!

## Questions & answers

**Q: How much body water can freeze?**  
A: Up to 65-70%. _(Source: Write-up · Exhibit A (Species) · Wikipedia: Wood frog)_

**Q: Heart while frozen?**  
A: No heartbeat. _(Source: Write-up · Exhibit B (Range) · Wikipedia: Wood frog)_

**Q: Protective compounds?**  
A: Cryoprotectants. _(Source: Write-up · Exhibit C (Frozen water) · Wikipedia: Wood frog)_

**Q: Where found?**  
A: Wide range. _(Source: Write-up · Exhibit D (Vital signs) · Wikipedia: Wood frog)_

**Q: When do they thaw?**  
A: Warming. _(Source: Write-up · Exhibit E (Protectants) · Wikipedia: Wood frog)_

## Sources

- [Wikipedia: Wood frog](https://en.wikipedia.org/wiki/Wood_frog)

## Cite this case file

Easterling, Marcus. "Feeling Froggy?." The Detail Department (DetailEnjoyer), case file DD-758, last updated Oct 25, 2026. https://detailenjoyer.com/case/feeling-froggy/